Manufacture of water, acid, and alkali proof articles.



I. L. ROBERTS. MANUFACTURE OF WATER, AUID,'AND ALKALI PROOF ARTIOLES;

APPLIOATION FILED 001.3, 1907. 921,000, Patented May 11, 1909.

- Way the .UNITED sTATEs PATENT OFFICE.

ISAIAH L. ROBERTS, OF LOCKPORT, NEW YORK.

MANUFACTURE OF WATER, ACID, AND ALKALI PROOF ARTICLES.

Specification of Letters Patent.

Patented May 1 1, 1909.

Application filed October 8, 1907. Serial No. 395,663.

To (I'll whom it may concern:

lzle it known that l. Isauu L. Ronnnrs, a citizen of the l nitcd States,and resident of Lockport. in the county of Niagara and State of NewYork, have." invented certain new and useful improvements in Manufactureof Water. Acidiand Alkali Proof Ar ticles. of which the following is aspecification.-

My invention relates to wood-pulp, strawboard or other woody material,to'be used with acids or alkalles or both, and has for its object toprovide an etfective process for rendering such articles liquid proofand also resistant to the attacks of acids and alkalies.

, l-leretofore numerous attempts have been made to utilize wood,woodpulp. etc, for a rticles to be used with acids and alkalies, forexample as containing receptacles or vessels for the same. A commonmethod for the purpose is to coat the surface of the article. or toimpregnate the article as deeply as possible, with acid and alkaliresisting niaterial: but it has been found that after an "article sotreated has been in use for a more or less short time the chemical,

especially if it be an acid, attacks the ends of the fibers at thecontact surface, and fol-' lowing these fibers soon permeates thearticle and greath impairs it or rendersit entirely useless.

My present invention also involves impregnation of the article as deeplyas pos sible. but in a novel manner, whereby a marked alteration of thecharacter of the woody material is effected, 'Withthe result that thefinished article is practically unatl'ackable by acids and alkalies.

In carrying out my invention in a simple article to be treated isimmersed in a bath of resistant material, such as resin, stearic acid,sulfur, linseed oil, paraflin, etc, the temperature ofwhich is ighenough to partially carbonizethe "article, The partial carbonization,which is not carried far enough to materially impair the strength of thearticle, renders the material thereof porous. into the pores andinterstices of which -the resistant substance of the bath enters. onremoving and cooling the article the terial solidifies in the pores,leaving the article liquid-proof and thoroughly resistant. If thearticle to be treated is bulky or thick, the bath is preferably at lowtemarticles of wood,-

tures of two or more of these. permeating or nnpregnatlng' 1113-perature when the article is placed therein, after which the temperatureis raised until the carbonization has proceeded as far as desired. Thetemperature is then reduced toa point. slightly above the melting pointof'the bath, after which the article 1s removed and allowed to drip and0001. In this way there is little if any absorption of the bath liquiduntil the water and gases liberated during the carbonization are allevolved, since the evolution thereof goes on while the temperature isrising, and so prevents the liquid from entering the pores. lmt when thetemperature falls the evolution ceases and the liquid inunediatelyenters, and penetrates to a greater depth than would be the case ifthetemperature remained high.

If desired the treatment may take place in a partial vacuum, thus makingthe process more rapid. in a vacuum the gases are evolved more. rapidly,and on restoration of atmospheric pressure the bath liquid is forcedinto the pores deeply and quickly. lfiurthermore, the temperature neednot be so high in a vacuum. since in a vacuum decomposition, that is,carbonization, takes place at a lower temperature.

A convenient apparatus for practicing the invention is illustrated inthe annexed drawing. which shows the same in vertical section.

The furnace is of brick, inclosed in an iron sheathing lt. In thefurnace is an iron vessel (1. of suitable size. to which are connected avalved exhaust pipe I). for connection with an airpulnp, and a valvedinlet pipe E by which air may be admitted at the proper time. The vesselis heated by suitable ,qas burners F.

In the vessel is the carbonizing and inipregnating bath. indicated by G.As previously stated. various substances can be used for the purpose:but the substance or substances used should be capable of withstandingthe necessary carboi'iizing temperature withoutdecomposition orprohibitory volatilization. Among such may be mentioned stearic acid.the resins. paraffin wax, sulfur, linseed oil, and asphaltum. and mix-Asphaltum. for instance is "too thick or viscous when heated to enterthe pores of the article readily, but paraflin or resin may be mixedwith the asphaltum 1n su'tlicient quantity to give the desired fluidity.The article will be waterproof if any of the substances mentioned beused, and also acid and alkali prooi if sulfur or paraflin be used. Ifstearic acid or resinyor a mixture of asphaltum and resin, be employed,the article will be acid proof but not alkali-proof, since thesubstances mentioned saponiiy in alkali. The articles, which are ofcourse lighter than the bath even when thoroughly impregnated, are keptsubmerged by a suitable weight, such as perforated iron plate H.l-lollow articles, such as the pails 1, tubes J, cup K, etc., as shown,should be placed on their sides, so'as to promote free circulation 1'or'plates, as L, may be placed below.

of the bath into and out of them. Sheets An air-tight cover, M, is nowplaced on the vessel (l, and the air exhausted through pipe D. As thearticlues become heated the evolution of air and'gases from the articlestakes place rapidly.. When the articles are suiticiently carbonized thevacuum is relieved by opening the inlet pipe and closing the exhaustpipe, whereupon the absorption of the bath liquid by the pores andinterstices of the articles is completed, the increased pressure causingthe liquid to permeate the articles thoroughly, as will be readilyunderstood. The articles are then removed, and allowed to drip and cool.In the case of bulky or thick-walled articles the exhaustion of thegases above the bath may be repeated several times, or the air-pump keptat work during the treatment, to insure complete permeation. Likewisethe tempera-ture' nay be low, say but slightly above the meltingpoint-of the. bath, at the start,

then raised to the carbonizing temperature,-

and then lowered, asprevimisly mentioned.

The temperature required for the carbonization. and the length of timethe articles should be treated in vacuo and under atmospheric pressurewill depend in general upon the size of the articles and the materialcoinposing the same, and for particular ma- -terials and conditions canbestbe determined by trial. Tests can easily be made wlth desiredmaterials and the. conditions necessary for the proper degree ofcarboniza tion and permeation can be readily found.

Articles treated as above described are completely liquid-proof and arepractically unattaclmble by acids and alkalies. At the same time thetreatment is inexpensive, .quick, and not difiicult to practice,requiring only reasonable carev and-attention on the part of theoperator. -What I claim is:

l.' The herein described method of treat- ,ing articles composed of.woody material to l i Witnesses:

o21,ooo

render the same water, acid, and alkaliproof, which consists inpartially carbonizing the article in a heated bath of water-' proofing,and resistant material and permitting the material of the bath topermeate the article.

2.. The herein described method of treatmg articles composed of woodymaterial to render the same water, acid, and alkaliproof, which consistsin immersing the article in a bath of res1stant material, heatingthe'bath till the articletherein is parproof, which consists inimmersing the' article in a bath of water-proof and resistant material,producing a partial vacuum above the bath and heating the bath with thearticle therein till the article is partially carbonized, and relievingthe vacuum above said bath.

The herein described method of treating articles composed of woodymaterial to render the same water, acid, and alkaliproof. which consistsin immersing the 'article in a bath of resistant material, producing apartial vacuum abovethe bath an d heating the bath till the articletherein 15 partially carbonized, and relieving the racuiun and loweringthe temperature of the bath.

(S. The herein described method of treating articles composed of woodymaterial to render the same water, acid, and alkaliproof, which consistsin immersing the article in a bath of water-proof and resistantmateriatliquefied by heat, partially .carbonizing the woody material ofthe article while in the loath and permitting the liquefied material ofthe bath to permeate the partially carbonized article, then removing thearticle from the bath and allowing the absorbed material of the bath toharden by cooling.

ISAIAH L. ROBERTS.

Jnssn PETERSON,

CHAs. E. Fomna.

